1. Field of the Invention
The present invention relates to a transistor circuit with protecting function, and more particularly a transistor circuit with protecting function packaged in a single package.
2. Description of Related Art
A conventional MOSFET has a safe operating area (SOA) and the safe operating area is determined by a largest current, a largest power, a largest voltage and a largest temperature that the MOSFET is able to handle without damage. The reliability of the MOSFET may be decreased, even damaged, when the MOSFET is operated out of safe operating area. In conventional arts, a protecting circuit is connected to the MOSFET externally. The protecting circuit detects a state of the MOSFET (such as a current flowing through the MOSFET), judges whether the MOSFET operates in the safe operating area and protects the MOSFET from being damaged.
However, not all MOSFET controllers detect the state of the MOSFET to protect it. The controller without MOSFET protecting function cannot make sure that the MOSFET operates in the safe operating area. In addition, if the MOSFET and the controller with MOSFET protecting function are packaged in different packages, the problem of noise interference and signal transmission delay may occur. Moreover, the protecting circuit for detecting the temperature of the MOSFET may have an error due to different packages.